Circuit Description

Vapor pressure sensor, canister closed valve Vacuum Switching Valve (VSV) and pressure switching valve VSV are used to detect faults in EVAP system. ECM determines if a fault is present in EVAP system based on the vapor pressure signal circuit.

DTC P0441 or P0446 is set if EVAP system leak is detected by ECM or if there is a malfunction in EVAP VSV, pressure switching valve VSV, or in vapor pressure sensor. Possible causes are:

Open or short in EVAP VSV circuit.
Open or short circuit in vapor pressure sensor circuit.
Open or short in canister closed valve VSV circuit.
Faulty canister closed valve VSV.
Faulty pressure switching valve VSV.
Faulty VSV for EVAP system.
Faulty vapor pressure sensor.
Disconnected, cracked, damaged or blocked vacuum hose.
Faulty charcoal canister.
Fuel tank cap installed incorrectly.
Damaged fuel tank cap.
Damaged fuel tank.
Damaged fuel tank overfill check valve.
Faulty ECM.

NOTE: If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate diagnostic test first before performing DTC P0440 diagnostic test.